From 1a56ef3e2b95395f22a9f0568ee20013aa4c193a Mon Sep 17 00:00:00 2001
From: Martin Mares <mj@ucw.cz>
Date: Sat, 25 Sep 2010 12:45:45 +0200
Subject: [PATCH] Placement macros, output routine

---
 ucwmac.tex | 78 +++++++++++++++++++++++++++++++++++++++++++++++++++---
 1 file changed, 75 insertions(+), 3 deletions(-)

diff --git a/ucwmac.tex b/ucwmac.tex
index 4943c80..3bb1091 100644
--- a/ucwmac.tex
+++ b/ucwmac.tex
@@ -1,3 +1,16 @@
+% We'll use internal macros of plain TeX
+\catcode`@=11
+
+%%% PDF output switch %%%
+
+\newif\ifpdf
+\pdffalse
+
+\ifx\pdfoutput\undefined
+\else\ifnum\pdfoutput>0
+	\pdftrue
+\fi\fi
+
 %%% Page size and margins %%%
 
 \newdimen\pagewidth
@@ -6,6 +19,7 @@
 \newdimen\rightmargin
 \newdimen\topmargin
 \newdimen\bottommargin
+\newdimen\evenpageshift
 
 \def\setuppage{%
 	\hsize=\pagewidth
@@ -18,16 +32,18 @@
 	\advance\hoffset by -1truein
 	\voffset=\topmargin
 	\advance\voffset by -1truein
-	\ifx\pdfpagewidth\undefined\else
+	\ifpdf
 		\pdfpagewidth=\pagewidth
 		\pdfpageheight=\pageheight
 	\fi
 }
 
-\def\sethmargins#1{\leftmargin=#1\relax\rightmargin=#1\relax}
+\def\sethmargins#1{\leftmargin=#1\relax\rightmargin=#1\relax\evenpageshift=0pt\relax}
 \def\setvmargins#1{\topmargin=#1\relax\bottommargin=#1\relax}
 \def\setmargins#1{\sethmargins{#1}\setvmargins{#1}}
 
+\def\setinneroutermargin#1#2{\sethmargins{#1}{#2}\evenpageshift=\rightmargin\advance\evenpageshift by -\leftmargin}
+
 \def\defpaper#1#2#3{\expandafter\def\csname paper-#1\endcsname{\pagewidth=#2\pageheight=#3\setuppage}}
 \def\setpaper#1{%
 	\expandafter\let\expandafter\currentpaper\csname paper-#1\endcsname
@@ -54,4 +70,60 @@
 \setmargins{1truein}
 \setpaper{a4}
 
-\bye
+%%% Placing material at specified coordinates %%%
+
+% Set all dimensions of a given box register to zero
+\def\smashbox#1{\ht#1=0pt \dp#1=0pt \wd#1=0pt}
+\def\smashedhbox#1{{\setbox0=\hbox{#1}\smashbox0\box0}}
+\def\smashedvbox#1{{\setbox0=\vbox{#1}\smashbox0\box0}}
+
+% Variants of \llap and \rlap working equally on both sides and/or vertically
+\def\hlap#1{\hbox to 0pt{\hss #1\hss}}
+\def\vlap#1{\vbox to 0pt{\vss #1\vss}}
+\def\clap#1{\vlap{\hlap{#1}}}
+
+% \placeat{right}{down}{hmaterial} places <hmaterial>, so that its
+% reference point lies at the given position wrt. the current ref point
+\long\def\placeat#1#2#3{\smashedhbox{\hskip #1\lower #2\hbox{#3}}}
+
+% Like \vbox, but with reference point in the upper left corner
+\def\vhang#1{\vtop{\hrule height 0pt\relax #1}}
+
+% Like \vhang, but respecting interline skips
+\def\vhanglines#1{\vtop{\hbox to 0pt{}#1}}
+
+% Crosshair with reference point in its center
+\def\crosshair#1{\clap{\vrule height 0.2pt width #1}\clap{\vrule height #1 width 0.2pt}}
+
+%%% Output routine %%%
+
+\newbox\pageunderlays
+\newbox\pageoverlays
+\newbox\commonunderlays
+\newbox\commonoverlays
+
+% Adding to {over,under}-lays
+\def\addlay#1#2{\setbox#1=\vbox{\ifvbox#1\box#1\fi\smashedvbox{#2}}}
+\def\pageunderlay{\addlay\pageunderlays}
+\def\pageoverlay{\addlay\pageoverlays}
+\def\commonunderlay{\addlay\commonoverlays}
+\def\commonoverlay{\addlay\commonoverlays}
+
+\output{\ucwoutput}
+\def\ucwoutput{\wigglepage\shipout\vbox{%
+	\makeheadline
+	\ifvbox\commonunderlays\copy\commonunderlays\nointerlineskip\fi
+	\ifvbox\pageunderlays\box\pageunderlays\nointerlineskip\fi
+	\pagebody
+	\ifvbox\commonoverlays\vbox to 0pt{\vskip -\vsize\copy\commonoverlays}\fi
+	\ifvbox\pageoverlays\vbox to 0pt{\vskip -\vsize\box\pageoverlays}\fi
+	\makefootline
+}\advancepageno
+\ifnum\outputpenalty>-\@MM \else\dosupereject\fi}
+
+\def\wigglepage{\ifodd\pageno\else\advance\hoffset by \evenpageshift\fi}
+
+%%% Cleanup %%%
+
+% Let's hide all internal macros
+\catcode`@=12
-- 
2.39.2